1. Field
Methods and apparatuses consistent with the exemplary embodiments relate to a mobile device which detects particulate matter and a method of sensing the particulate matter.
2. Description of the Related Art
There is an increasing interest in particulate matter (PM) as a source of air pollution. Accordingly, requests to sense the PM by using small mobile devices are increasing.
PM sensors include a flow meter which induces an air flow and measures a flow rate, and a sensor which detects the PM. The sensor may be classified into, for example, a light-scattering type, a weight type, an electric signal type, and an inertial mass type, according to a detecting method.
In order to apply the PM sensor to a mobile device, the PM sensor has to be miniaturized. Additionally, components of the PM sensor have to be replaced periodically, in order to obtain an accurate sensed value. For example, a weight type sensor collects PM by passing air through a filter of the weight type sensor and senses an amount of the collected PM, but it is difficult to sense the amount in real-time since a collecting time is required, and the filter needs to be periodically replaced. An electric signal type sensor is applied to a diesel particulate filter (DPF) device of a car, wherein the electric signal type sensor only detects whether an amount of PM is equal to or higher than a reference amount, and requires an apparatus for removing PM on a sensing plate by using heat. An inertial mass type sensor transmits PM to a certain location and indirectly measures a weight of the sunken PM, wherein a quartz crystal microbalance (QCM) method is mainly used to measure the weight. A QCM needs to be periodically replaced. A light-scattering type sensor emits light on a sensing region where air passes through and collects light scattered by PM, wherein the light-scattering type sensor itself may be miniaturized, but a flow meter that supplies air and measures a flow rate has a relatively large size.